Starting issue update...... Today I changed the alternator, with fingers crossed and lucky rabbit's foot present, started the car. The alternator did not changes the starting issue. I do have a new check valve now and waiting for a nice day to install it. To be continued......again........
Since this thread is seven months old you will do better getting responses starting a new one..........
Let me guess. If you drive the car for 30 minutes, stop, then start it five minutes later you do not have the problem? this is the exact problem I had on my 1981 320i. Yes, I know that car is 20 years older than yours. Anyway, I got so frustrated that I took it in our best local independent shop. For what it's worth, they replaced the thermo time switch, bascially the switch that tells the car it's cold wasn't reading and the cold start valve was staying closed. $88. Starts on the first try now, though I've significantly shortend the starter motor's life because I didn't deal with the issue sooner. Don't know if newer cars have the same equipment, but I would bet whatever they replace this part with is the source of your problem.
Same issue for me. Hello Adam, Did you ever get this starting issue resolved? I seem to have a similar problem with my 99 M coupe.